Astrocytoma is the most common maligant brain tumor in humans and is currently incurable due to its diffusely infiltrative behavior. We have developed a mouse model of astrocytoma that recapitulates the infiltrative behavior of human astrocytoma. In this mouse model the tumor suppressor genes Nf1 and p53 are mutated. We are using this mouse model to examine the signal transduction pathways necessary for proliferation and migration of astrocytoma cells both in vivo and in vitro. An understanding of these mechanisms will lead to the development of new therapies for astrocytoma.